This Standard specifies the signalling protocol for the support
of the Common Information additional network feature (ANF-CMN)
at the Q reference point between Private Integrated services Network
eXchanges (PINX) connected together within a Private Integrated
Services Network (PISN).

ANF-CMN is an additional network feature which enables the exchange
of Common Information between entities acting on behalf of the
two ends of a connection through a PISN. This Common Information
is a collection of miscellaneous information that relates to the
user or equipment at one end of a connection and includes one
or more of the following: Feature Identifiers, Party Category,
Equipment Identity. This information, when received by an entity,
can be used for any purpose, e.g. as the basis for indications
to the local user or to another network or in order to filter
feature requests.

Additional network feature specifications are produced in three
stages and according to the method described in ETS 300 387. This
Standard contains the stage 3 specification for the Q reference
point and satisfies the requirements identified by the stage 1
and stage 2 specifications in ECMA-250.

The signalling protocol for ANF-CMN operates on top of the signalling
protocol for basic circuit switched call control, as specified
in ECMA-143, and uses certain aspects
of the generic procedures for the control of supplementary services
specified in ECMA-165.

This Standard also specifies additional signalling protocol requirements
for the support of interactions at the Q reference point between
ANF-CMN and other supplementary services and ANFs.

NOTE
Additional interactions that have no impact on the signalling
protocol at the Q reference point can be found in the relevant
stage 1 specifications.

This Standard is applicable to PINXs which can interconnect to
form a PISN.

The protocol defined in this Standard forms part of the PSS1
protocol (informally known as QSIG).